Celiac and the Microbiome

I thought this was one of the more interesting and, in a way, hopeful stories I’ve read in the last few weeks.

Celiac is yet another autoimmune disease with a rising incidence in the industrialized world.   Those who suffer from it have an abnormal immune reaction to the protein gluten which is found in many grains.  Eating gluten sets off an autoimmune attack on the lining of the small intestine affecting a person’s ability to absorb nutrients from food.  The only known treatment is a life-long gluten-free diet, which is difficult to maintain as it is highly restrictive.

Apparently, there is a gene (HLA genotype) that is highly associated with the development of the celiac.  However, while the majority of people with celiac carry the gene, many people with the gene do not develop the disease.  Therefore, there must be an environmental trigger.  Epidemiological data shows that type of delivery (i.e. natural versus Caesarean), intestinal infections, antibiotic use, and milk feeding practices (i.e. breast versus formula) all have an effect on the future development of the disease.  That is, variation in bacterial microbiome seems to play a pivotal role.

Researchers in Spain[i] compared the gut bacteria of 10 healthy newborn babies who had relatives with confirmed celiac to 10 controls infants (who did not develop celiac after 5 years).  Their gut bacteria was analyzed at 4 months and at 6 months:  the control babies had an escalating increase in bacterial diversity over time, compared to the babies who developed celiac.  The babies who went on to develop the disease had several specific bacterial differences and also, immune markers, which in the future may serve as biomarkers for the likelihood of developing the disease.

 “The microbiota of infants who remained healthy showed an increase in bacterial diversity over time, characterized by increases in Firmicutes families, but not those who developed CD….An increased relative abundance of Bifidobacterium longum was associated with control children while increased proportions of Bifidobacterium breve and Enterococcus spp. were associated with CD development.”

Levels of selective IgA, antibodies of the digestive system, were significantly lower in the infants who went on to develop celiac.  The researchers hypothesize that this may be caused by bacterial shifts, leaving the mucosal lining vulnerable to invasion by unfriendly microbes, and abnormally reactive to antigens:  “…it can be hypothesized that a premature reduction of sIgA levels in the group of children that developed CD could be related to shifts in bacterial community development which impact the maturation of the mucosal immune functions, possibly increasing the risk of developing autoimmune dysfunctions.”

The hope is, of course, that these differences may be modifiable, meaning that if corrected, the babies can be protected from developing celiac.  Imagine that idea in a more global sense: maybe someday well-baby visits will include routine analysis of babies’ microbiomes to ward off inflammatory diseases!

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[i] Olivares M, Walker AW, Capilla A, et al. Gut microbiota trajectory in early life may predict development of celiac disease. Microbiome. 2018;6:36. doi:10.1186/s40168-018-0415-6.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5819212/